This invention relates to a new and improved method and structure for supporting a superconducting winding on a support structure by means of interface lining material having a low shear modulus of elasticity, whereby frictional heat generated by relative sliding motion at the interface surfaces of the electrical winding with the support structure, is minimized.
More particularly, the invention relates to such a method and structure which is specially suited for use in the fabrication of superconducting windings of the type that are saddle-shaped and comprised of a number of superconducting conductor elements held together in a large bundle by epoxy resin to form relatively large stator or rotor windings for cryogenic generators and motors in order to overcome the problem of degradation of winding performance caused by frictional heat generated by relative sliding motion between such windings and their support structures.
The stator and/or rotor windings of cryogenic electrical generators and motors generally are comprised of two or more nested saddle-shaped superconducting windings with each saddle-shaped winding being comprised of a plurality of superconducting conductors that are bunched together in close thermal and electrical contact with each other and secured in a solid winding bundle by epoxy resin. While the epoxy-impregnation of the bundle of superconducting conductors solves the problems of degradation of winding performance that could be caused by individual conductor motion within the larger bundle winding, the epoxy-impregnation techniques do not solve the problems of winding performance degradation caused by relative sliding motion between the epoxy impregnated saddle-shaped winding bundle and the support structure for the winding bundle hereafter referred to as the saddle-shaped winding. Saddle-shaped windings fabricated in the above-described manner when electrically excited and placed in operation encounter substantial centrifugal and magnetic forces which make it extremely difficult to prevent relative sliding motion between such windings and their support structure. Relative sliding motion between the winding and the support structure causes sufficient local heat to be generated due to friction so as to raise the temperature of at least portions of the winding above the critical temperature of one or more of the superconducting conductors comprising the winding. Thus, the frictionally-generated heat results in degradation of winding performance.